6MPQ image
Deposition Date 2018-10-08
Release Date 2019-02-27
Last Version Date 2023-11-15
Entry Detail
PDB ID:
6MPQ
Title:
1.95 Ang crystal structure of OXA-24/40 beta-lactamase in complex the inhibitor ETX2514
Biological Source:
Source Organism:
Host Organism:
Method Details:
Experimental Method:
Resolution:
1.95 Å
R-Value Free:
0.20
R-Value Work:
0.18
R-Value Observed:
0.18
Space Group:
P 41 21 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Beta-lactamase
Gene (Uniprot):blaOXA-33
Chain IDs:A
Chain Length:245
Number of Molecules:1
Biological Source:Acinetobacter baumannii
Modified Residue
Compound ID Chain ID Parent Comp ID Details 2D Image
KCX A LYS modified residue
Primary Citation
Targeting Multidrug-ResistantAcinetobacterspp.: Sulbactam and the Diazabicyclooctenone beta-Lactamase Inhibitor ETX2514 as a Novel Therapeutic Agent.
MBio 10 ? ? (2019)
PMID: 30862744 DOI: 10.1128/mBio.00159-19

Abstact

Multidrug-resistant (MDR) Acinetobacter spp. poses a significant therapeutic challenge in part due to the presence of chromosomally encoded β-lactamases, including class C Acinetobacter-derived cephalosporinases (ADC) and class D oxacillinases (OXA), as well as plasmid-mediated class A β-lactamases. Importantly, OXA-like β-lactamases represent a gap in the spectrum of inhibition by recently approved β-lactamase inhibitors such as avibactam and vaborbactam. ETX2514 is a novel, rationally designed, diazabicyclooctenone inhibitor that effectively targets class A, C, and D β-lactamases. We show that addition of ETX2514 significantly increased the susceptibility of clinical Acinetobacterbaumannii isolates to sulbactam. AdeB and AdeJ were identified to be key efflux constituents for ETX2514 in A. baumannii The combination of sulbactam and ETX2514 was efficacious against A. baumannii carrying blaTEM-1, blaADC-82, blaOXA-23, and blaOXA-66 in a neutropenic murine thigh infection model. We also show that, in vitro, ETX2514 inhibited ADC-7 (k2/Ki 1.0 ± 0.1 × 106 M-1 s-1) and OXA-58 (k2/Ki 2.5 ± 0.3 × 105 M-1 s-1). Cocrystallization of ETX2514 with OXA-24/40 revealed hydrogen bonding interactions between ETX2514 and residues R261, S219, and S128 of OXA-24/40 in addition to a chloride ion occupied in the active site. Further, the C3 methyl group of ETX2514 shifts the position of M223. In conclusion, the sulbactam-ETX2514 combination possesses a broadened inhibitory range to include class D β-lactamases as well as class A and C β-lactamases and is a promising therapeutic candidate for infections caused by MDR Acinetobacter spp.IMPORTANCE The number and diversity of β-lactamases are steadily increasing. The emergence of β-lactamases that hydrolyze carbapenems poses a significant threat to our antibiotic armamentarium. The explosion of OXA enzymes that are carbapenem hydrolyzers is a major challenge (carbapenem-hydrolyzing class D [CHD]). An urgent need exists to discover β-lactamase inhibitors with class D activity. The sulbactam-ETX2514 combination demonstrates the potential to become a treatment regimen of choice for Acinetobacter spp. producing class D β-lactamases.

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